The present invention is concerned with master batch compositions comprising an organic peroxide, a plasticiser and a filling material and possibly further additives compatible with the organic peroxide.
Masterbatch is a designation frequently used in the rubber and plastics industries for pre-mixtures and primary mixtures of additive materials, for example anti-oxidants, inhibitors, mastication adjuvants and the like, in concentrated rubber and plastics mixtures. In the form of master batch compositions, the additives necessary for further working up, although only present in small amounts, can be more easily dosed and homogeneously incorporated.
The master batch compositions, which contain various additives, for example organic cross-linking peroxides, which are thereby more easily dosable and homogeneously workable, are to fulfil various requirements: they are, for example, independently of the nature of the elastomeric carrier and of the nature of the organic peroxide (in solid or liquid form), to be easily and reliably preparable and workable and also to show, in the case of a high proportion of filling materials, a good elasticity and incorporability into elastomers of the rubber industry and are not to bleed out (migration of the additive materials, for examle of the peroxide, on to the surface) and are to be storage-stable.
According to DE-A-21 23 214, rubber chemicals are used in the form of granulated mixtures of elastomers, the rubber chemicals in question and possibly dispersion agents. Because these mixtures are used in the granulated form the master batch compositions are readily capable of being mixed in and pollution due to dust and smell is to be avoided.
EP-A-0 423 639 and U.S. Pat. No. 5,238,978 describe master batch compositions in which 10 to 70% by weight of an organic peroxide is homogeneously dispersed in a polycaprolactone carrier.
It is an object of the present invention to provide master batch compositions which can be produced in a simple and reliable way with the use of conventional apparatus known for such compositions, for example kneaders, and with which there is obtained as many as possible of the properties desired for such master batch products. This object is achieved by means of the present invention.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects obtained by its use, references should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention .